In NASA's Dreams: Laser-Launched Rockets and Deep Space Cruisers

With the space shuttles soon bound for retirement homes, NASA is dreaming up the future of U.S. human space flight. Recently, NASA has divulged its interest in two new gadgets: rockets launched via lasers and reusable, manned, deep-space crafts. Now, all the agency needs is a plan to get more money from the government to actually build these things. The lasers (or possibly microwaves) would be ground-based, and would shoot through the air to energize a rocket's heat exchanger; elevating the rocket's fuel to over 3,100 degrees Fahrenheit would give it more thrust.